Oil-grinded recycled kapok fiber as a bio-packing for eco-friendly modified asphalt and its aging resistance behavior

The aging of asphalt binder is one of the vital factors to shorten the service life of asphalt pavement. The researches on delaying the aging of asphalt binder by different fibers are extremely valuable. The recycled kapok fiber (KF) mixed into the asphalt improves the properties of the matrix microscopically and achieves the effect of delaying aging. It still needs to modify KF because of its hygroscopicity and water absorption. It results in the lack of adhesion with the asphalt interface. This paper studies a liquid-phase ball-milling technology for KF with waste engine oil (WEO) as a grinding medium. Through the mechanical force activation, it optimizes the size and surface properties of KF and finally prepares the oil-grinded kapok fiber modified asphalt binder (OKFA). After scanning electron microscope (SEM), X-ray diffractometer (XRD), nitrogen adsorption-desorption method (BET) and Fourier transform infrared spectroscopy (FTIR) tests, the structure of KF and OKF was characterized. It showed that the crystallinity of oil-grinded kapok fiber (OKF) increased by 11.5% compared with KF, and the specific surface area and pore volume increased by 74.3% and 62.5%, respectively. Through the accelerated aging test, nanoindentation and viscosity and other correlation tests were used to evaluate the mechanical properties and aging performance of the modified asphalt. It showed that OKFA performed good aging resistance and potential low-temperature resistance enhancement of asphalt. This research not only solves the resource recycling and reuse of textile fiber waste and follows the new development of energy-saving and environmental protection, but also provides a new direction for improving the performance of asphalt.